2015 Volume 33 Issue 2 Pages 20s-24s
For quantitative evaluation of solidification cracking susceptibility in two kinds of type 316FR stainless steel (316FR-A and 316FR-B) laser welds, laser beam welding (LBW) transverse-Varestraint test was performed. As the welding speed increased from 1.67 to 40.0 mm/s, enlargement range of solidification brittle temperature range (BTR) for 316FR-B (from 14 to 40 K) was larger than that for 316FR-A (from 37 to 46 K), respectively. Based on theoretical calculations for solid/liquid coexistence temperature range by using Kurz-Giovanola-Trivedi and solidification segregation models, the reason for larger increment of the BTR for 316FR-B could be regarded as larger decrement of δ-ferrite amount during the welding solidification than that for 316FR-A, affecting severe increment of the impurities' segregation (S and P), thereby more enlarging the solid/liquid coexistence temperature range as compared with that of 316FR-A.
